Year	Percent
1970	0.2551
1971	0.47481
1972	0.53167
1973	2.07336
1974	0.70008
1975	0.95488
1976	-0.14928
1977	0.4289
1978	1.16555
1979	0.18182
1980	0.08574
1981	0.02808
1982	-0.10805
1983	-0.05022
1984	0.02631
1985	-0.02117
1986	-0.05377
1987	-0.22956
1988	0.0492
1989	-0.01612
1990	-0.28999
1993	0.3256
1994	0.00278
1995	0.01763
1996	0.02159
1997	0.04652
1998	0.02176
1999	0.03074
2000	0.17663
2001	0.32166
2002	2.73611
2003	1.87403
2004	1.59821
2005	1.27585
2006	0.87028
2007	0.57671
2008	0.4876
2009	0.72053
2010	0.74917
2011	0.73294
2012	0.77844
2013	0.65251
2014	0.48461
2015	0.53126
2016	0.80482
2017	1.14194